SIMI VALLEY, CA - SEPTEMBER 16: : Republican presidential candidates Mike Huckabee and Marco Rubio take part in the presidential debates at the Reagan Library on September 16, 2015 in Simi Valley, California. Fifteen Republican presidential candidates are participating in the second set of Republican presidential debates. (Photo by Justin Sullivan/Getty Images)

SIMI VALLEY, CA - SEPTEMBER 16: Republican presidential candidates Carly Fiorina and John Kasich take part in the presidential debates at the Reagan Library on September 16, 2015 in Simi Valley, California. Fifteen Republican presidential candidates are participating in the second set of Republican presidential debates. (Photo by Justin Sullivan/Getty Images)

SIMI VALLEY, CA-SEPTEMBER. 16: Republican presidential candidate Rand Paul take part in the presidential debates at the Reagan Library on September 16, 2015 in Simi Valley, California. Fifteen Republican presidential candidates are participating in the second set of Republican presidential debates. (Photo by Justin Sullivan/Getty Images)

Carly Fiorina, former chairman and chief executive officer of Hewlett-Packard Co. and 2016 Republican presidential candidate, speaks during the Republican presidential debate at the Ronald Reagan Presidential Library in Simi Valley, California, U.S., on Wednesday, Sept. 16, 2015. After a friendly round of introductions, the second Republican presidential debate quickly plunged into clashes that shifted from policy to the personal, with more politically experienced insiders trying to gain an advantage against the front-runner at center stage: Donald Trump. Photographer: Max Whittaker/Pool via Bloomberg

SIMI VALLEY, CA - SEPTEMBER 16: Republican presidential candidates Chris Christie (R) and Ohio Gov. John Kasich take part in the presidential debates at the Reagan Library on September 16, 2015 in Simi Valley, California. Fifteen Republican presidential candidates are participating in the second set of Republican presidential debates. (Photo by Justin Sullivan/Getty Images)

SIMI VALLEY, CA - SEPTEMBER 16: Republican presidential candidates Donald Trump (L) and Jeb Bush take part in the presidential debates at the Reagan Library on September 16, 2015 in Simi Valley, California. Fifteen Republican presidential candidates are participating in the second set of Republican presidential debates. (Photo by Justin Sullivan/Getty Images)

SIMI VALLEY, CA-SEPTEMBER. 16: Republican presidential candidate Donald Trump takes part in the presidential debates at the Reagan Library on September 16, 2015 in Simi Valley, California. Fifteen Republican presidential candidates are participating in the second set of Republican presidential debates. (Photo by Justin Sullivan/Getty Images)

2016 Republican presidential candidates Carly Fiorina, former chairman and chief executive officer of Hewlett-Packard Co., and Scott Walker, governor of Wisconsin, walk on stage during the Republican presidential debate at the Ronald Reagan Presidential Library in Simi Valley, California, U.S., on Wednesday, Sept. 16, 2015. The main debate of the top 11 GOP contenders in the polls follows the 'kids' table' debate of candidates who didn't make the cut. Photographer: Patrick T. Fallon/Bloomberg via Getty Images

SIMI VALLEY, CA - SEPTEMBER 16: Republican presidential candidate Donald Trump speaks with reporters after the presidential debate at the Reagan Library on September 16, 2015 in Simi Valley, California. Fifteen Republican presidential candidates are participating in the second of presidential debates(Photo by Sandy Huffaker/Getty Images)